Doctors are embarking on a “catch-up” campaign to prevent the spread of the disease, which is now at its highest level for almost two decades across England and Wales.

Experts say they are particularly worried about the number of outbreaks in several parts of the country among older children and teenagers, many of whom missed vaccinations when they were toddlers in the wake of the MMR scare.

Prof David Salisbury, head of immunisation at the Department of Health urged parents across the UK to see the ongoing epidemic in Wales as a “clarion call” to protect their own children.